The subject of this proposal is an international scientific meeting on "Multicellular Behavior of Bacteria: In Nature, Industry and the Laboratory." The objective of the conference is to examine the importance of bacterial multicellularity in a wide range of situations, including environmental biofilms and colonies, bioreactors, bacterial pathogenesis, and bacterial development on laboratory media. It is expected that new insights will emerge into the roles of cell-cell communication and multicellular organization in bacterial activity. Research on Bacteria as multicellular organisms is health-related in several areas. Infectious disease: Surface colonization, phase variation, group motility, elaboration of extracellular polymers and resistance of multicellular aggregates to antibacterials are all key aspects of bacterial pathogenesis. Dental: Formation of organized biofilms and plaque is central to oral disease. Environmental: Metabolic interactions and organized bacterial communities are important in the bacterial degradation of toxic pollutants. Cancer: Bacteria provide model systems for studying genetic change and the origin of clonal populations displaying neoplastic growth control.